LAUSR

The ability to produce byssal threads enables invasive dreissenid mussels to attach to recreational boat hulls and other equipment. These mussels can be exposed to air during overland transport of recreational boats, which affects their potential to survive transport. Survival during air exposure is determined by a variety of environmental factors such as temperature, relative humidity, shaking and vibrations and the movement of air. This study assessed the influence of air movement on the survival and behavioural changes of the quagga mussel (Dreissena bugensis). Survival time decreased significantly when mussels were exposed to a wind speed of 10 and 50 km.h compared to standing air survival. Mussel clumps survived significantly longer than mussel individuals. The lethal time of 99% of mussel individuals (LT99) decreased from 29.26 to 18.24 hours when exposed to a wind speed of 50 km.h. At a wind speed of 10 km.h LT99 survival times of mussel clumps (26.94 h) were higher compared to individual mussels (19.76 h). Valve gaping behaviour changed when mussels were exposed to flowing air. Mussels exposed to a wind speed of 10 km.h were on average open for 6.41% of the time, whereas in standing air mussels were on average open for 26.78% of the time. These results indicate that air movement has an influence on the survival potential of aerially exposed quagga mussels. Management of invasive alien mussels should take into account that the quagga mussel can survive air exposure with an wind speed of 50 km.h over 18 hours when attached to boat hulls. 50% of the mussels can be transported alive for distances over 300 km and 1% of the mussels can be transported alive for more than 900 km. Decontamination of boats and associated equipment will be vital for improved spread-prevention of invasive mussels.